1. Field of the Invention
The present invention relates to a gas sensor for measuring a concentration of a predetermined gas component in a measurement gas, specifically to a gas sensor for measuring a concentration of nitrogen oxide (NOx).
2. Description of the Background Art
Conventionally, various measuring devices have been used for finding out a concentration of a desired gas component in a measurement gas. A known device of measuring a NOx concentration in a measurement gas such as a combustion gas, for example, is a gas sensor having a Pt-containing electrode and a Rh-containing electrode formed on an oxygen ion conductive solid electrolyte, such as zirconia (ZrO2) (see Japanese Patent Application Laid-Open No. 2006-284223, for example).